What are the advantages and disadvantages of fighter canard layout?

Today, many advanced fighters adopt duck layout, such as typhoon, gust and eagle lion, including ours.

J 10。

American fighter planes, such as F 15, F 16, F 18, F22 and F35, are all in the traditional layout. Balance, stealth.

Duck wings are not fun when they reach high performance.

One of the reasons why the United States refuses the duck layout is the balance problem. If the canard is designed according to the principle of effective pitch control, then the canard cannot balance the huge bow moment generated by the wing high-lift device. If it is necessary to trim the high-lift device, then the canard must be enlarged and the downwash of the wing will be increased, thus weakening the high-lift effect. Moreover, in order to prevent deep stall, it may be necessary to increase the flat tail. On the other hand, from the point of transonic area rule, canard is difficult to meet the requirements of transonic area rule, which increases the difficulty of fuselage design and supersonic drag, especially for ATF which emphasizes over-patrol.

Another important reason for rejecting duck layout is invisibility. It is difficult to unify the position, size, plane shape and stealth requirements of canards. An important principle of stealth design is to reduce (but inevitably) the discontinuity on the surface of the body (especially in the head-on direction), and the canard is just difficult to make a sword. If we want to minimize the number of main beams corresponding to the leading and trailing edges of the wing (that is, the leading and trailing edges are parallel), it will bring greater design difficulty.